The Sum of All Cities

There are more than 10,000 cities around the world and 55% of the world's population - over 4 billion of us - call them home.There are more than 10,000 cities around the world and 55% of the world's population - over 4 billion of us - call them home.There are more than 10,000 cities around the world and 55% of the world's population - over 4 billion of us - call them home.